Modern image forming apparatuses have a power saving mode function for reducing power consumption during a period in which it is not used by a user. Also, there are cases where image forming apparatuses include a human detection sensor that reacts if a user approaches the image forming apparatus in the power saving mode, and the apparatus returns from the power saving mode to a normal operation. A sensor such as a pyroelectric sensor or an ultrasonic sensor is used as the human detection sensor.
Japanese Patent Laid-Open No. 2015-512212 discloses a technique for achieving Wi-Fi connection by providing a modern terminal such as a smartphone with an NFC function through which authentication data is transmitted to the terminal from an apparatus without a user inputting settings. Furthermore, Japanese Patent Laid-Open No. 2004-363670 discloses a technique in which a terminal such as a smartphone is provided with a speaker or a microphone, communication is performed using a sound wave output from the speaker, and data such as authentication information is exchanged.
However, the above-described conventional techniques have the following problems. For example, the image forming apparatuses according to the conventional techniques use an ultrasonic sensor as the human detection sensor for shifting from the power saving mode to normal operation, and have the NFC function or the like in order to perform authentication with respect to a terminal such as a smartphone. However, providing such an image forming apparatus with both the ultrasonic sensor for human detection and the NFC function for authentication causes the problems of increased cost and additional places for installation being needed. Therefore, there is a demand to use one ultrasonic sensor, or to use one control unit to control an ultrasonic sensor, to be able to achieve both human detection and communication for transmitting authentication data. However, there is no clear rule as to when these functions are to be switched. Another problem is that a frequency for communication (18 kHz to 22 kHz) output from an ultrasonic sensor will create an audible sound that is unpleasant to those who can hear it, and thus it is preferable for the ultrasonic sensor not to output the frequency for communication.